Switch contact construction



June 13, 1950 w. H. LINDAE SWITCH CONTACT CONSTRUCTION Filed Aug. 22, 1946 //\/\/E/\/7O WILLIAM H. LINDAE Patented June 13, 1950 UNITED Williamlli Lindaeg.ShLonisrMoc,laissignoriofiones halfl to eEola, Lindae and one -,halfe to Joseph-1R;

H me

This invention relates in-generalt'o certaincnew and useful improvements in-- electrical switches and; more particularly,- to those of the lm-iie type; The usual knife switch comprises a-single blade for eachcircuit' to be made or'broken that is', a single-pole switch comprises one blade hingediy engaged at one endbetween" contacts: pressing against both sides ofthe blade, which: end is called the a hinge jaw-, and; rotatably' engaging anddlsengaging at the other end opposed spring contacts, called'-the-break jaw! I n-m-yeinvem tion, however, a pair of parallel blades is" em ployed, which eng-agabetweem them,- at -both the hinge and the-- break ends, clips with spheri cally rounded' contact faces.

The primary object of the presentinventiomis to provide a double. knife-typeelectrical switch with spherical contact surfaces-- interposect between the blades 1 at both the hingeand the break ends.

A further object ofthe present invention is-to provide a switch having a-p'lura'lity 'ofspherical contact surfaces which in the actuation of the switch connect: and disconnect quicklyand posi tivel-ya Anadditional object of the-present invention is try provide a switch with: spherically forlned contact-on bearing: pointsreinforced with-- silver or other metal suitable forlong weafing electrical contacts;

Another object of the, present invention is to provide a high-capacityelectrical switch whose currentitransmittmg: parts; may be. economically fabricated from flat metal, and: are; readily? sembled and easily; replaced.

A further object of the present invention is to. provide a switch of the type; stated having; an"

ventilated contactposts for-readily dissipating heat generated by contact arcing and current conduction.

The above and other objects will become more fully apparent from the following; specification, which, by,way of illustrationlrather than, limita tion, sets forth preferred processesaand preierregl forms of apparatus constitutin embodiments of the present invention, th scop of which is defined in the appended claims.

In the accompanying drawings:

Figure 1 is a top plan view of a switch constructed in accordance with and embod ing my invention;

Figure 2 is a side elevational view of the switch, the open or disconnected position thereof being indicated in dot-dash lines;

Y cai plane along whlch t 4 Fig-urea is a vertical sectional view taken alon lin '33of'Figure2; =and Figure/idea;vertical sectional-vievwtakemalong line-44 of IE ig-u-re 2? Referringnowdn moi e detail and byireieren'ce characters to the drawings, which illustrate: a preferred embodiment of the presentinventiom A design-ates: a switch com-prisingi two potietype, porcelain insulator s I conventionally mounted-sin suitably spaced relation upon the steelwonki oi a transmissiomtowen or some, other supporting structure (not/:- shown) Molded; or otherwise mounted in and projecting upwardly-immathefim sulators I arelstildSZ, andimcun-ted thereoneby meansof: nuts-:1 aree terminal; bloclesl 4 having binding-i nostss 51 for; the attachmenti-oii bussl bars 6t 'liheinner a ,endsi of termina-L blocks it-are providedzwithcalpair ofipara'llellmilledislots l f or: tightly" reeeiving: upright: contact posts 8, the: latter beingsretainedtthereini by press iitted pins-8 passing: through-laterally drilledsapertures Ills; Hi5 inlcorltacttblccks AiandSpostsQE respece tively,

Each of: said i contacta posts -8'-.- consists of: two halves symrnctr-Really formed-. from} fiat copper stock, their upper end-portions;l l beingbentlint wardly and mitered to: bean tiglrrtly agair'1stce'ach othen and thereby be retained in spaeedeparallel relation to permit; tree circulation ofi air. therebetween ion ventilatiorw purposes: Be neatli their inwardly bent upperend portions it; the contaet posts? are-e twaidiyemwn, pressed; stamped or embessed irr the provision of protrud ing sphei ical portions i2? at-r the outen-on con taetingy surfaces-=oi which are silver inserts t3? together iorm a; s 7 thesuriace ofw hich port-ions l'ifmeet: IhEtlfe-preferr shown; there are-iour suclr ball ike con althcugh more or"less-than-= four}m -:y read y mPlQ d heie desi ed. It willbe notedt-hat the-posts*8fi5tedi3 attached to the insulators l at both the hinge end (shown at right in Figure 1) and the break end (shown at left in Figure 1) are substantially identical. However, at the so-called hinge end, contact post 8 is laterally drilled as at M to receiv hinge bolt i5 which, by means of radiall split spring washers I6 and nut I1, holds the blades l8 with adjustable tension against the silver contact inserts l3 of the contact post -8 at that end. At the other, or break end, terminal block 4 is tapped to receive bolts I9 securing to it the fixed latch keeper 20.

The break ends of blades I8 are laterally drilled near their extremities to receive bolt 2I which, together with nut 22, holds between said blades I8 a channel-shaped spacer 23 and a rockably mounted latch lever 24 having a hook 25 adapted to engage the latch keeper 20. At its upper end, the latch lever is provided with a ringshaped latch handle 26. Bolt 2I also passes through, and together with nut 22 holds adjacent to the outer surfaces of blades I8, leaf springs 21 having bent outer ends 28 and inwardly protruding embossed spherical portion 29 whereby to space said Springs 21 with reference to the outer surfaces of blades I8. Also mounted in and extending through the break ends of blades I8 is a bolt 30 provided at its threaded end with a nut 3| for connecting the inner ends of leaf springs 21. By adjusting nut 3|, any desired amount of spring pressure may be exerted by the inwardly-extending spherical portions 29 of springs 21 against the outer surfaces of blades I8 in the vicinity of the engagement and electrical contact of their inner surfaces with the interposed contact post 8 at the break end of the switch.

The method of assembly and disassembly of the switch for the replacement of parts is apparent from the construction shown and correct alignment of the parts follows inherently from the spring pressures against the several spherical contact surfaces.

Switches constructed as disclosed herein, whether of the single-pole single-throw type as illustrated or of more complex detail, as of multiple-pole, double-throw type, operate with a minimum of friction, due to the ball-like contacts, This permits higher contact pressures, which, together with the self-aligning feature, results in more positive electrical contact than would otherwise be possible. At the break end of the switch, the movement of the blades into and out of engagement with the several spherical contact faces is progressive, so that the contact is made and broken quickly.

It should be understood that changes and modifications both in the methods as Well as in the form, construction, arrangement and combination of the several parts of the switch may be made and substituted for those herein shown and described without departing from the nature and principle of the present invention.

, Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In electrical switches of the type described, an electrical contact postcomprising two symmetrically-formed pieces of electrically conductive metal rigidly mounted at their lower ends in terminal blocks, the upper ends of said pieces normally bearing against each other and having matching outwardly protruding sphericallyrounded portions formed on and protruding from the sides thereof. 7

2. In electrical switches of the type described,

a ventilated electrical contact post comprising two symmetrically formed members rigidly mounted at their lower ends in spaced relation in a terminal block, the upper ends of said members being bent inwardly and mitered for normally bearing against each other, said members further having opposed outwardly presented matching spherical protuberances, each such protuberance being provided upon its contact surface with a silver contact insert.

3. In electrical switches of the type described, a ventilated electrical contact post comprising two symmetrically-formed members rigidly mounted at their lower ends in spaced relation in a terminal block and being at their upper ends bent inwardly providing end portions having mitered inner faces disposed in abutment against each other, said members further having opposed outwardly protruding spherically-rounded portions, each such protruding portion being provided at its contact surface with a silver contact insert.

4. In electrical switches of the type described, an electrical contact post comprising two symmetrically-formed members rigidly mounted at their lower ends in spaced parallel relation in a terminal block and being at their upper ends bent inwardly providing end portions having mitered inner faces disposed in abutment against each other, said members further having opposed outwardly protruding portions, each such protruding portion being provided at its contact surface with a silver contact insert.

5. A ventilated switch post comprising a base member having two spaced parallel slots, and a pair of identically shaped plates having fiat lower portions sized for snug fitting disposition within the slots respectively and projecting upwardly therefrom in spaced parallel and marginally aligned relation to each other, said plates being angularly bent over at their upper ends and mitered providing end faces, said end faces being in abutment against each other whereby to provide an upwardly pointed end for the post and at the same time hold the lower portions of the plates in spaced parallel relation for substantially their entire length, said plates being provided upon their outwardly presented faces respectively with matching protuberances providing oppositely presented contact points.

WILLIAM H. LINDAE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 670,145 Bossert Mar. 19, 1901 1,052,975 Schoenman Feb. 11, 1913 1,229,750 Holt June 12, 1917 1,988,687 Jackson Jan. 22, 1935 2,193,238 Ramsey Mar. 12, 1940 2,200,509 Lindae May 14, 1940 2,208,411 Crabbs July 16, 1940 2,274,410 Harlow Feb. 24, 1942 

